Atmospheric Radiation Measurement (ARM) Climate Research Facility

Cloud Life Cycle Infrastructure

An important component of any long-term atmospheric measurement
program is the quality control and maintenance of the datastreams from
instrument systems. Further, the raw measurements from atmospheric
remote sensing instrumentation are not directly useable by the majority
of the scientific community. These raw measurements must be interpreted
and converted to geophysical quantities that can be more readily used by
a greater number of scientists to address important questions regarding
the Earth’s climate system.

The cloud life cycle infrastructure group at BNL is led by
Dr. Michael
Jensen and is responsible for the development and production of
cloud-related value-added products (VAPs). The cloud life cycle
infrastructure group also provides mentorships for the millimeter cloud
radar datastreams (Karen Johnson) and the ARM disdrometers (Mary Jane
Bartholomew). A major focus of value-added product activities is
the retrieval of geophysical properties from millimeter cloud radar
observations.

Group Products

Active Remote Sensing of Clouds (ARSCL)

The ARSCL VAP combines data from multiple active remote sensing
instruments to produce an objective determination of cloud hydrometeor
height distributions and best-estimates of their radar reflectivities,
vertical velocities, and Doppler spectral widths. Much of the
algorithm's calculations deal with ensuring accuracy and optimally
merging data from the millimeter cloud radar's sequential operating
modes, which have various advantages and limitations. [Developer:
Karen
Johnson]

Micro-ARSCL

The Micro-ARSCL VAP is a microscale cloud radar data product with the
radar’s high temporal resolution. It includes information about the
local maxima in each Doppler spectrum, uncertainty estimates for the
Doppler moments of the primary peak, Doppler moment shape parameters
(e.g., skewness and kurtosis), and more accurate identification of radar
clutter. [Developer: Edward Luke]

Merged Sounding

The Merged Sounding VAP uses a combination of observations from
radiosonde soundings, the microwave radiometer, surface meteorological
instruments, and European Centre for Medium Range Weather Forecasts
model output with a sophisticated scaling/interpolation/smoothing scheme
in order to define profiles of the atmospheric thermodynamic state at 1
minute intervals and a total of 266 altitude levels. [Developer:
David
Troyan]

Continuous Baseline Microphysical Retrieval (MICROBASE)

The MICROBASE VAP uses a combination of observations from the
millimeter cloud radar, ceilometer, micropulse lidar, microwave
radiometer and balloon-borne sounding profiles in order to determine the
profiles of liquid/ice water content, liquid/ice cloud particle
effective radius and cloud fraction. This baseline retrieval is
calculated every 10 seconds and then averaged over 20-minute intervals
with a vertical resolution of greater than 230 levels. [Developer:
Maureen Dunn]

Principal Investigator

Mission

Obtaining detailed measurements of the life cycle of clouds is an important step
towards understanding these processes and constraining their representation in models.

The conversion of raw measurements from complicated remote sensing observations into
geophysical quantities that can be utilized by the larger scientific quantity is an
important activity for the BNL cloud life cycle infrastructure group. This figure shows
a time-height profile of radar reflectivity from the ARM millimeter cloud radar, which
has been one of the cornerstone instruments of the ARM Facility.

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U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical,
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University of New York on behalf of Stony Brook University, the largest academic user of Laboratory
facilities, and Battelle, a nonprofit applied science and technology organization.